1. Field of the Invention
The present invention relates to inventive flexible applicators for electric field capacitive coupled energy transfer or for simple heating by current flow through means formed from a conductive metal coated flexible material. The improved energy transfer means is a flexible, porous, light and easy to manipulate treatment electrode.
2. Description of the Relevant Art
Heating is widely applied in many areas of medicine and also used for cosmetic treatments. For example Radiofrequency/microwave hyperthermia devices can be used to force energy absorption in tissue to cause damage to unwanted structures and/or increase the temperature of a targeted area above the normal body temperature. One use of hyperthermia devices is the treatment of cancer. In the case of cancer treatment, tumor cells are more sensitive to stresses, for example, heat and/or electromagnetic fields and chemical treatments, than the surrounding normal tissue cells. Therefore the aim is to pump sufficient energy to the tumor tissue to irreversibly damage the tumor cells, but which can be tolerated by normal tissue cells. Another use for hyperthermia devices is to increase temperature and blood circulation for cosmetic (fat-burning, lipid-distortion, shape-correction, etc), dermatological and pain relief treatments.
Conventional non-invasive electrical field hyperthermia devices commonly use as an energy transfer means two bolus electrodes placed on opposing sides of the target tissue to be heated. Other non-invasive hyperthermia solutions use radiative antennas or phase-array set of antennas to pump the desired energy into the requested area, cooling also the immediate surface by water-bolus application. Other solution could be the direct heating of the applicator to reach the desired temperature directly on the skin surface. These arrangements are optimized to deliver energy to a small target area and is not suitable for the treatment of a large target area.
For example WO 2004/107816 A discloses an apparatus of flexible and “breathable” electrical heater which is heated up independently, and heats up the underneath skin by heat diffusion. The device is also useful for drug delivery of heat-liberated drugs on the skin.
U.S. Pat. No. 4,164,226 centers on the iontophoretic effects with unidirectional (DC) current. No capacitive coupling with continuous AC/RF is disclosed in U.S. Pat. No. 4,164,226 where the load is a complex impedance of the treated body part.
WO 99/52424 A discloses a typical intraluminar applicator which it not suitable for treating the outer surface. The applicator is based on DC or pulsed DC current, having iontophoretic or electroporation effects.
WO 00/47274 A is directed to an apparatus for iontophoretic or electroporation applications. The applicator is flexible and the invention is in its topological solution. This type of treatment performed with the applicator of WO 00/47274 A has direct contact with high voltage and low current (microamperes), while the applicator of the present invention is for RF conduction having under 100 V and high current (Amps).
U.S. Pat. No. 5,486,182 discloses an apparatus for intraluminar and/or intracavital electro-cauterization (ablative electric burn). This apparatus and the method performed with such apparatus is directly an inside application (like in WO 99/52424 A) and the cauterization made by inside mechanical cage to remove the polyp.
None of the prior art literature describes an applicator for RF conduction having under 100 V and high current for generating heat inside the body, while the energy-absorption is caused by the RF-current which flows through the body and makes the heating in-situ deep. The device of the present invention applies continuous AC or RF, high current low electric field for the deep heating of tissue which is not disclosed in the afore-mentioned prior art documents.